Eliminating disturbing energy



Patented Apr. 21, 1925.

UNITED STATES PATENT oer-ice.

REGINALD A. nnssnnnnn, or nnooxnmn, MASSACHUSETTS, ASSIGNOR 'ro SUBMA- amn SIGNAL COMPANY, or PORTLAND, MAINE, A CORPORATION or MAINE;

ELIMINATING DISTURBING ENERGY.

Application filed August 20, 1917. Serial No. 187,121.

To all whom it may concern:

Be it known that I, REGINALD A. FESSEN- DEN, of Brookline, in the county of Norfolk and" State of Massachusetts, a citizen of the United States, have invented a new and useful Improvement in Eliminating turbing Energy, of which the following is the specification.

My invention relates to the generation, transmission, and utilization of energy and more particularly to the generation and receipt of signals and still more particularly to the elimination of-disturbing signals and influences and water noises, such as cause disturbance in submarine signalling and detecting submarines.

The object of my invent-ion is to obtain increased efliciency in these lines.

The drawing shows diagrammatical mechanism embodying my invention In Fig. 1, 11 is a receiver for signals; for example, as shown, an oscillator, such as described in U. S. Patent No. 1,167 ,366 which translates such signals into electrical impulses and hence may be termed a receiving transmitter. The leads 12 and 13 of the oscillator go to a rectifier 14, the frequency of which is adjusted by the regulator 15 for example of the type described by applicant in his paper on Wireless telephony (Transactions of the American Institute of Electrical Engineers, July, 1908), or as shown a simple rheostat. The leads from the rectifier are connected through the choke coils 16, 16' to an interrupter, 18, the frequency of which is regulated by the regulator 23. 15 and 23 may be field rheostats which are used as required.

The circuits containing the choke coils 16, 16 may be shunted by the condensers 17, 17', as shown as is well known in the art of producing practically steady rectified currents from alternating currents (see'Steinmetz, Transient Electrical Phenomena, pages 236-248).

The leads from the interrupter 18 may proceed through theamplifier 19 and leads 21, 20 to the'ear piece 22. i

In operation the interrupter 18 is adjusted to any suitable frequency, as found by experiment. The rectifier 14 is then varied until the operator listening in with the ear piece 22 hears the signal or noise which he desired to hear come in as plainly as possible.

Dis-

the rectifier 14 be adjusted to a frequency 30, then the sound emitted by the submarine having frequency 30 will be rectified to substantially continuous current and later passed through the choke coils 16, 16', which may have an inductance of the order of a henry ,the condensers 17 17 having any suitable value, as is well known in the art (see Steinmetz, Transient Electrical Phe nomena, pages 236-248), without substantial loss ordiminution, and these continuous or slowly pulsating currents being received by the interruptor 18 will be broken up into a high frequency current of that pitch to which the ear is most sensitive, ap-

proximately 920, and the efi'ects they produce may be heard either directly on the receiver 22 or, being free from disturbing efiects produced by water noises, can be amplified before reaching the receiver 22.

In this way the water noises and other disturbing noises are eliminated because having as a rule frequencies different from 30 they will not be rectified by the rectifier 14 into continuous or slowly pulsating currents but will remain alternating currents and will even, in most cases, have their frequency raised by the commutator so that the choke coils 16, 16 and condenser 17 will entirely prevent any except the most minute portion of them from passing onward to 18, and the minute remainder will be still further diminished by18.

This combination acts as a very simple, eflicient, and very sharply selective variable filter and is hence of use wherever such filters are desired, and is also of use for other purposes. This method of selecting or filtering out disturbing impuzlses has many advantages over the older resonance methods discovered by Hertz, Tesla, applicant and others. It will do many things I described is a radically new means of which the resonant method cannot accom plish. For example:-

1. If the frequency of the signal is so low as to be inaudib e, say 10 per second, then after'selection -b resonance methods it will be inaudible, a' d must be chopped in accordance with the method invented b applicant, and for. which alp'atent was a lowed him. But this chop mg will take lace at varying points on ewave, and by iourier analysis this can be shown equivalent to a broad band of frequencies, thus weakeni the selectivity and preventin further se ection.v With the present method this is not the case; the final note is pure and even. V I

2. If the f uenc is so high as to be inaudible, with e o d resonance method it must be cho ped, with great loss of efliciency. Or i? passed through a 'li uid barretter or tellurium receiver or the li e, there will be at loss due to the resistance of the receiver, amounting generally to thousands of ohms, which less is avoided in the present method. I

3. Harmonics can pass in resonance methods, which cannot pass with present method. 4. With this method, the same device has .been operated over a range of more than 1 to 1,000, i. e. thev maximum frequency being more than 1,000 times the min1mum..

With resonance methods, the inductance would have to be 9,000,000 times as great for the minimum frequency as for the maximum.

5. The selectivity is substantially indendent of the length of the wave train, i. e. 1s substantially as sharp for a train 'of 4 wave lengths as for one of which is not the case with resonance methods.

It will be seen that the method herein roducing selectivity. Heretofore this has n accomplished by resonance methods, but the method herein described is entirely independent of resonance as' it will be noted that if a desired frequency is to be selected the first commutating rectifier 14 is adjusted to 0 rate at the desired frequency and there y turns the desired impulses into a substantially continuous current, while all the undesired frequencies remain of an alternating current character. That this substantially continuous current reduced from the oscillators of the desire frequency flows without substantial loss or impedence through the choke coil 16 and after flowin through it is acted upon by the secon commutator to produce a note or indication at any desired frequency, whereas all the undeslred frequencies were kept back by the choke coil 16. In practice selective curves obtained with the apparatus hereby described have been found to be much sharper than those obtained by resonance methods.

What I claim is: r

1. Apparatus for the utilization of the energy of electric impulses; generator of electric impulses, receiving conductors, an interrupter, .a choke coil, a second commutator, and a device for utilizing the energy of electric currents, in series in the order iven; whereby electric currents flowing cm the receiving conductors to the first commutator, and of a desired f uency, are commutated into substantia y continuous currents by means'of the.

first commutator; and currents of undesired frequencies are not so commutated; and the passage of the energy of the currents of undesired frlefluencies is opposed b the choke coil, w e the passage of the su stan- .comprising a tially continuous current is not so opposed by said choke coil; and said substantially continuous current is then commutated to periodic currents of a desired frequency by the said second commutator; and said penodic currents utilized in said electric energy utilizing device. I

2. The method of selecting periodic electric current of a desired frequency, flowing in an electric circuit, from currents of undesired uencies flowing in said electric circuit; which consists in first commutating said current of desired frequency into substantiall continuous current; secondlyoposing t e flow of said currents of undesired e uencies while permitting the flow of s'ai substantially continuous current; and thirdly commutating said substantially continuous current into current of -a desired periodicity.

3. The method of selecting from other and undesired impulses, impulses of a' desired frequency, and of .utihzin said impulses of a desired frequency, w ich consists in rectifying said impulses of a desired frequency by a commutating rectifier o erating at .a commutation frequency su stantially the same as .the frequency of the imtpulses to be utilized, then passing said rectied impulses throughan electric. circuit element which is resistant to the flow of non.-,

rectified impulses, and substantially nonresistant to the flow of rectified impulses, thereby permitting mainly and substantially only the rectified lmpulses to pass, and then interrupting, by a second interrupting device, said rectified impulses into interrupted impulses of the frequency at which it is desired to utilize said im ulses.

4.. That method of ellminating disturbing noises from sounds desired to be received which consists in receiving said noise and sound impulses upon a receiver whereby they will be transformed into electrical impulses, adjusting a rectifier to the frequencies of the sound impulses desired to be received and transmitting said electrical impulses thereto whereby those impulses of the frequency of the rectifier will pass there- 1 through and be rectified into-a continuous current, separating said rectified current from all unrectified impulses, breaking up said rectified current into a high frequency current and delivering it to an indicator.

5. Apparatus for the utilization of the energy of electric impulses, comprising receiving conductors, a commutator, a choke coil, a second interrupter, and a device for utilizing the energy of electric currents, in series in the order given; whereby electric currents flowing from the receiving conductors to the first commutator, and of a desired frequency, are commutated into substantially continuous currents; by means of the first commutator; and currents of undesired frequencies are not so commutated; and the passage of the energy of the currents of undesired frequencies is opposed by the choke coil, While the passage of the substantially continuous'current is not so opposed by said choke coil; and said substantially continuous current is then commutated to periodic currents by the second commutator; and said periodic currents utilized in said energy utilizing device.

REGINALD A. FESSENDEN. a 

